There has been proposed a magnetic disk device which includes a hard disk and has a function called Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.). The device uses the S.M.A.R.T. function to acquire a device operation history, an error history, and the like and performs failure prediction for a device using the acquired history information (see Japanese Patent Application Publication No. 2001-312375, Japanese Utility Model No. 3178766, and Japanese Utility Model No. 3178767). If failure is predicted, the magnetic disk device notify such the result of failure prediction to a user by displaying a warning message on a monitor of a computer connected to the magnetic disk device or turning on or flashing an LED lamp disposed on a casing of the magnetic disk device.
The S.M.A.R.T. function performs a failure prediction based on a frequency of some type of failure which has actually occurred in the magnetic disk device, such as the number of bad sectors subjected to alternative processing, the number of times that sector alternative processing has occurred, or the number of times that seek errors have occurred. Therefore, there is a problem that fatal failure may occur before as a result of failure prediction is obtained indicating that a possibility of fatal failure is high. In this case, a user cannot back up data stored in the magnetic disk device. Further, there is a problem that even in the situation where any fatal failure has not occurred, the user cannot recognize whether a probability of failure in the magnetic disk device is high, i.e., whether it is time to replace the magnetic disk. The above-described problems are not limited to the magnetic disk devices including hard disks and are common to magnetic disk devices including other magnetic disks such as flexible disks and Zip disks. Therefore, it is desired to provide techniques capable of accurately specifying whether a probability of failure in the magnetic disk device is high.